There is presently in progress an exponential growth in the variety of new communication technologies and functionalities which are being developed and currently presented for public use. The implementation of such technologies has in one way or another resulted in highly increased demands upon the facilities of the public switched telephone network (PSTN). While many of these technologies have been publicized as virtual substitutes for the PSTN, the fact is that their implementation has increased the usage of all or parts of the networks which are operated by local exchange carriers or LECs. This phenomena threatens not only to degrade the quality of performance of the local PSTN but also to produce potentially serious network overload to the detriment of virtually all network services. The problems which have been caused or imminently threatened pose difficult questions by their very variety and unforeseen nature.
By way of example: Recent legislative and regulatory changes require that a local exchange carrier (LEC) unbundle certain network elements and services and offer use of those elements and services to other carriers for resale to end users. In one required implementation, the LEC will sell the other carrier an unbundled port on an end office switch and allow the other carrier to become a competing local exchange carrier (CLEC) by reselling services of the switch to end users having local loops which connect to the end office switch.
Those statutory and regulatory changes also specify that the enhanced service known as customized routing be made available for both unbundled switching and for resale. Customized routing is the term used in the regulations for routing calls made in the local exchange carrier (LEC) switch to locations other than those that exist today. The primary applications are for unbundlers and resellers to have operator (0+, 0-) calls and directory assistance calls (411/555) routed to their own platforms. Other types of calls could possibly be applicable as well, but the 0+/0-/411 calls are the ones in most immediate demand.
This type of customized routing in an interconnection environment represents a capability that currently does not exist in the network architecture of LECs. The currently used switches in the LEC public switched telephone networks were not designed with this functionality in mind. The capability does not exist and the switches are not readily adaptable to provide customized routing. This applies to all of the predominantly deployed switches (5ESS, 1AESS, EWSD, and DMS-100) from three major switch manufacturers, Lucent Technologies (formerly AT&T), Nortel, and Siemens.
One prospective unbundler and reseller has suggested use of line class codes (LCCs) to accomplish this purpose. However, any implementation of customized routing using LCCs would require use of an excessive number of such codes and would produce other serious problems. Not only is there a limit to the capacity of the switch regarding the number of LCCs that could be physically provisioned, managing the new operational environment is at least as critical. The provisioning and maintenance systems that support the LEC's services cannot be ignored. These systems allow telephone services to be ordered, provisioned, monitored, repaired, and billed; they are an essential element in contributing to the quality of service enjoyed today by the public LEC's customers.
Without incorporating new LCCs into the operations systems that support services, severe problems would have to be expected in provisioning services. Manual provisioning would require human intervention and complex lookups that involve locating the correct code in a table of thousands. Such a process would be prone to both error and delay resulting in service degradation. It is for this reason that today's process is mechanized. In an environment with considerably more codes, a mechanized process would be even more important.
The line class code approach would use existing switch resources in a manner that was never intended. Such an application is untested and to some degree would have unknown consequences if deployed on any meaningful scale. Even the proponent of this approach has indicated that LCCs would be an interim and limited workaround which would need to be reversed once a longer term solution could be developed.
Another proposal for coping with the problem has been the possible use of an Advanced Intelligent Network (AIN) common channel signaling (CCS) solution. However, this is not feasible in view of the fact that, while the AT&T 1AESS switch has AIN capability, it will not apply AIN type processing to 0 calls. In that switch, the 0 number routing functionality takes precedence over all other types of call processing, including AIN processing.
As another example, it is common knowledge that usage of the computer network known as the Internet has increased tremendously. Internet Service Providers (ISPs) such as America On Line and Compuserve are connected to the Internet via high speed lines, such as T1/T3 and the like, and generally do not have their own Internet based Autonomous Systems but have or use dial-up networks connected to the PSTN. Personal computers (PCs) and Laptop computers are representative of computers connected to the Internet via the public switched telephone network (PSTN) and ISPs via dial up links.
Aggressive competition by regional ISPs has recently induced a number of the larger national ISPs to offer flat-rate pricing coupled with intensive advertising. This has been received with enthusiasm with the result that leading systems are frequently overloaded. More and more users are buying computers which are sufficiently powerful to send video and photographs, which constitute data-intensive material that can clog lines. In addition, more and more companies are using the Internet to conduct their business, communicate with and support their customers, exchange electronic mail with hundreds of thousands of users, seek and find valuable information. The most common forms of the overload are twofold. Customers frequently encounter busy signals due to lack of ISP contracted line capacity following the dialing of a hunt-group type directory number. This produces a complete inability for the customer to connect to the ISP.
As another example of a new type of traffic to be handled by the PSTN of LECs reference is had to U.S. Pat. No. 5,200,993, issued Apr. 6, 1993 to Wheeler et al., entitled Public Telephone Network Including a Distributed Imaging System. That patent describes a PSTN having enhanced capabilities with a distributed imaging system. The imaging system interfaces with end users through appropriate bridges, routers and gateways to provide the user with a virtual local area network. Automatic number information (ANI) is used to automatically configure the system as required by the user.
As a still further example of new uses for the PSTN, U.S. Pat. No. 5,247,347, issued Sep. 21, 1993 to Litteral et al., entitled PSTN Architecture for Video-on-Demand Services, describes the use of a PSTN to provide digital video signals from a video information provider to one or more of a plurality of subscriber premises. A subscriber uses either a standard telephone instrument over the PSTN or a dedicated control device over an ISDN packet network to order video programming. Connectivity between a central office and subscriber is provided by asymmetrical digital subscriber line interface units over the telephone local loop. The interface units frequency multiplex digital video information with voice information to the subscriber and support transmission of a reverse control channel from the subscriber to the central office for transmission on the ISDN packet data network back to the video information provider. The interfaces also allow base band signaling and audio between the central office and the subscriber for conventional telephone instrument connectivity.
U.S. Pat. No. 5,583,863, issued Dec. 10, 1996 to Darr, Jr., entitled Full Service Network Using Asynchronous Transfer Mode Multiplexing, describes an arrangement for transporting digital broadband data output in Asynchronous Transfer Mode (ATM) cell streams from a plurality of video information service providers (VIPs) to a plurality of subscribers.
In addition to the foregoing it has become commonplace to use so called Intelligent Peripheral (IP) platforms to provide a variety of services to subscribers through the central office switch with repetitive iterations between the switch or service switching point (SSP), service transfer point (STP), and integrated service control point (ISCP), and between the ISCP and the IP. Thus while the IP adds functionality to the service it nevertheless requires both voice and signaling traffic with the switching system in the central office. An example of such an arrangement is found in U.S. Pat. No. 5,572,583, issued Nov. 5, 1996 to Wheeler, Jr. Et al., entitled Advanced Intelligent Network with Intelligent Peripherals Interfaced to the Integrated Services Control Point. That patent describes an intelligent peripheral platform used in the advanced intelligent network (AIN). The IP assumes some functions presently performed by the ISCP and central office switches. Among its functional capabilities are voice announcement, digit collection, speech recognition and an array of other enhanced call processing features, such as voice or facsimile messaging.
Still further proposals for use of the facilities of the PSTN involve the provision of long distance telephone service via the Internet. This service loads not only the voice circuits but also the common channel signaling network.
All of the foregoing entail increased traffic, increased signaling, and increased connection time delays. When it is considered that current dial-up usage of the Internet through ISPs now includes day long sessions it will be appreciated that serious public network overload is predictable if not already existing.